Originally Posted by
noglider
Oh come on, doesn't that effectively restrict output?
No.
Replacing my 1998 Audi A4 US DOT headlights with 1999 E-code European parts satisfying those restrictions subjectively put at least 3X more light on the road in spite of the sharp cut-off and using the same bulbs.
It does mandate larger reflectors and housings (~2 inches in diameter not walnut sized) to provide both brightness and beam control.